What Weathers Marble & Limestone?

Temperature

• Temperature swings from hot to cold can form cracks in limestone or marble as the rock expands and contracts. Over time, these cracks will increase in size and weaken the rock, causing it to crack and break into smaller pieces. In addition, ice crystals and minerals, such as quartz and calcite, can precipitate in the cracks of the limestone and marble rocks and cause them to expand and break as the crystals grow.

Gravity and Movement

• The movement of marble and limestone rocks may cause physical weathering. Movement occurs because of wind, rain or gravity. This movement may result in small or large-scale erosion from a gentle roll down a hillside to a full landslide. During this movement, the marble and limestone may break if the force is sufficient on the rocks. The movement of rock particles will also cause those rocks to form rounded edges as they slowly wear away.

Animals and Plants

• Animals and plants are sometimes the cause of physical weathering of marble and limestone rocks. Animals can move rocks or rock pieces and cause them to drop from heights and break or force them to roll downhill, which can wear the edges of the rock or break it apart. Plants may grow through cracks in a marble or limestone boulder or outcrop and cause the crack to become larger as the plant grows. As the crack size increases, the marble or limestone will break apart into smaller pieces.

Water and Acid Rain

• Marble and limestone rocks are very susceptible to erosion by water and acid rain. Water from rainfall, streams and rivers pouring over and hitting the rocks will slowly wear away the surface of the stones. Over time, the marble and limestone will become smooth and decrease in size. Marble and limestone river rocks form from the action of water on the rock as they move down the river. Acid rain has a significant effect on marble and limestone. Carbonic, sulfuric or nitric acid are components of acid rain that will react with the calcium carbonate in the marble and limestone to pit and dissolve the rock over time.